Transgenic non-human mammals expressing a reporter nucleic acid under the regulation of androgen response elements

ABSTRACT

A transgenic non-human mammal whose genome comprises a nucleic acid construct, wherein said construct comprises a reporter nucleic acid encoding a reporter operably linked to a promoter comprising an androgen response element (ARE), and said construct further comprises an androgen receptor nucleic acid encoding an androgen receptor, and wherein expression of said reporter nucleic acid is regulated by expression of said androgen receptor nucleic acid. The transgenic non-human mammals can be used as an in vivo model for the identification and development of selective androgen receptor modulators (SARMs) for the treatment of cancer or other disorders associated with defective androgen receptor function.

[0001] This application claims the benefit of U.S. Provisional Application No. 60/396,501 filed July 17, 2002, whose contents are incorporated by reference in its entirety.

FIELD OF THE INVENTION

[0002] The present invention is directed towards a transgenic non-human mammal for the in vivo evaluation of androgen receptor function. The invention further pertains to the use of such mammals in the development of compounds and therapies that modulate androgen receptor activity.

BACKGROUND OF THE INVENTION:

[0003] Recent advances in recombinant DNA and genetic techniques have made it possible to introduce and express a desired gene sequence in a recipient animal. Through the use of such methods, animals have been engineered to carry non-naturally occurring sequences or genes, that is, sequences or genes that are not normally or naturally present in the unaltered animal. The techniques have also been used to produce animals which exhibit altered expression of naturally present gene sequences.

[0004] Animals produced through the use of these methods can be either “chimeric” in which only some of the animal's cells contain and express the introduced sequence or gene or “transgenic” in which all of the cells of the animal contain the introduced sequence or gene. Consequently, in the case of transgenic animals every animal is capable of transmitting the introduced genetic material to its progeny as compared to the chimeric animals in which transmittal to progeny is dependent upon whether the introduced material is present in the germ cells of the animal.

[0005] The high efficiency transformation of cultured mammalian cells has been accomplished by direct microinjection of specific DNA sequences into the cell nucleus (M. Capecchi, Cell 22:479-488 (1980)). More specifically, it has also been demonstrated that DNA could be microinjected into mouse embryos and found in the resultant offspring (J. Gordon et al., P.N.A.S. U.S.A. 77:7380-7384 (1980)). Thus, the ability to produce certain transgenic mice is described and well known in the art.

[0006] The basic procedure for producing transgenic mice requires the recovery of fertilized eggs from newly mated female mice and then microinjecting into the male pronucleus of said egg the DNA that contains the sequence or gene to be transferred into the mouse. The microinjected eggs are then implanted in the oviducts of one-day pseudopregnant foster mothers and allowed to proceed to term. The newborn mice are then tested for the presence of the microinjected DNA by means known in the art and appropriate to detect the presence of the microinjected DNA. See, for example, T. Wagner et al., P.N.A.S. U.S.A. 78:6376-6380 (1981), U.S. Pat. No. 4,873,191, which describes the production of mice capable of expressing rabbit beta-globin in its erythrocytes.

[0007] Androgens are steroid hormones mainly responsible for male sexual characteristics during development and in adulthood. In a normal adult man, approximately five to seven milligrams per day of testosterone (T), the principal androgen, are produced and released by the testis into the systemic circulation. testosterone or its more potent metabolite, dihydrotestosterone (DHT) (K. Sundaram, Steroid Biochem. Mol. Biol. 53:253-257 (1995)), binds to the androgen receptor (AR), a member of the steroid nuclear-hormone-receptor (NHR) superfamily. These intracellular receptors are ligand-dependent transcription factors that regulate the transcription of a variety of genes. The AR is widely distributed among reproductive and non-reproductive tissues, including the prostate and seminal vesicles, male and female genitalia, skin, testis, ovary, cartilage, sebaceous glands, hair follicles, sweat glands, cardiac muscle, skeletal and smooth muscle, gastrointestinal vesicular cells, thyroid follicular cells, adrenal cortex, liver, pineal, and numerous brain cortical and subcortical regions, including spinal motor neurons (A. Negro-Vilar, J. Clin. Endocrinol. Metab., 54(10):3459-62 (1999)). Testosterone can also be metabolized in secretory and target organs to oestrogen (oestradiol-17β) by aromatases (M. Sawaya et al., J. Invest. Dermatol. 109: 296-300 (1997), C. Roselli et al., Biol. Reprod. 58: 79-87 (1998)), and affect gene expression through the estrogen receptor.

[0008] The effects of androgens are multiple. In the embryo, they are responsible for the differentiation of the reproductive organs into the male phenotype. During puberty, the increase in androgen production induces the secondary sexual characteristics. In addition, androgens also affect other aspects of human life such as social behavior, sexuality and physical appearance.

[0009] For example, it has been reported that castration, which causes a cessation of testosterone, leads to a decrease in the aggression in animals (J. Morley, Handbook of Clinical Psychoneuroendocrinology, Nemroff, C. B. and Loosen, P. T. (editors), Guilford, N.Y., pp. 3-41 (1987)). Low testosterone levels have also been associated with fatigue, while testosterone replacement often produces a general feeling of well being Nolten W. E., Curr Urol Rep. 4:313-9 (2000). It has been shown that testosterone improves memory in male mice (J. Flood, P.N.A.S. U.S.A. 89:1567-1571 (1992)), and two placebo controlled studies in older males have found that testosterone improves visuospatial cognition (J. Jankowsky, Behav. Neurosci. 108:325-332 (1994)). In addition, it is believed that androgens have an effect on the vascular system in that studies suggest an inverse relationship between the free testosterone plasma levels in men and the degree of coronary heart disease in these subjects (G. Phillips et al., Arterioscler. Thromb. 14:701-706 (1994), K. English, Eur. Heart J. 21:890-894 (2000)). Infusion of testosterone into the coronary arteries of men with coronary artery disease results in an acute significant increase in coronary blood flow (C. Webb et al., Circulation 100:1690-1696 (1999)). Androgens have also been shown to have beneficial effects on endothelial cell function (Ong et al., Ann. J. Cardiol. 85:14-17 (2000)) and myocardial ischaemia (C. Webb et al., Ann. J. Cardio. 83:437-439 (1999); K. English, Circulation 102:1906-1911 (2000)). In terms of sexuality, testosterone clearly improves libido both in cross-sectional (R. Schiavi et al., Psychosom. Med. 53:363-374 (1991)) and in interventional studies (Morales et al., J. Urol. 157(3):849-854 (1997); I. Klepsch et al., Endocrinologie 20(4):289-293 (1982)). Regarding the effect of androgens on appearance and body composition, there are several studies in men that support the concept that testosterone improves muscle strength in older males with low levels of testosterone (R. Baumgartner et al., Mech. Ageing Dev. 107(2):123-136 (1999); R. Sih et al., J. Clin. Endocr. Metab. 82:1661-167 (1997); R. Orrell et al., J. R. Soc. Med. 88:454-46 (1995)). In terms of the effects of androgens on bone, it has been shown that bone mineral density declines with age in men (H. Burger et al., Ann. J. Epidem. 147(9):871-879 (1998)), and is increased in hypogonadal older males receiving testosterone replacement therapy (P. Snyder et al., J. Clin. Endocr. Metab. 84:1966-1972 (1999); I. Reid et al., Arch. Intern. Med. 156:1173-117 (1996)).

[0010] Despite the lack of a precise understanding of the mechanisms by which androgens act on so many physiological relevant systems, it is readily understood why the AR is an important target in multiple areas of drug discovery and patient therapy. In the oncology area, for example, inhibitors (antagonists or partial antagonists) of androgen receptor function are useful for the treatment of androgen dependent prostate cancer while agonists or partial agonists of the AR are applicable to the treatment of breast cancer. For metabolic and endocrine diseases disorders, agonists or partial agonists of the androgen receptor function are useful for the treatment of age-related diseases and conditions of cachexia in several disease states including, but not limited to, Acquired Immune Disease Syndrome (AIDS). Functional AR has also been identified in various bone cells and, as such, androgen administration has beneficial effects on skeletal development and maintenance in men and women.

[0011] The advancement of androgen therapy has been limited by the inability to separate desirable androgenic activities from undesirable or dose limiting side effects. Recent advances in the development of selective estrogen receptor modulators (SERMs) which have a degree of tissue selectivity in targeting the estrogen receptor while eliminating or minimizing undesired side effects, suggests that a similar approach may be feasible for other NHR, such as, selective androgen receptor modulators (SARMs). See, for example, A. Negro-Vilar, J. Clin. Endocr. Metab 54(10):3459-3462 (1999); P. Reid et al., Investigational New Drugs 17:271-284 (1999).

[0012] To date, several approaches have been taken in order to unveil the androgen receptor function in vivo. The testicular feminized male (tfm) mouse (M. Lyon et al., Nature 227:1217-1219 (1970)), which represents an example of loss of function, possesses a single point mutation in the N-terminal region of the AR gene that results in a premature stop codon (M. Gaspar et al., Proc. Natl. Acad. Sci. U.S.A., 88:8606-8610 (1991)). Tfm mice are equivalent to complete androgen insensitive syndrome (cAIS) in man and are genetically considered to be males that are infertile. They are therefore unable to be used for the generation of mice genetically considered to be female homozygous for the AR gene mutation. By breeding tfm carrier females with males that were chimeric for the AR gene mutation, only a few number of homozygous tfm females were generated. Studies performed on these latter animals revealed that having a functional AR is not critical for their reproductive capabilities (M. Lyon et al., Proc. R. Soc. Lond. B. Biol. Sci., 208:1-12 (1980)). However, there is a limitation in the use of these animals for the elucidation of the AR function in the adult mouse. Since the animals lack the receptor throughout life, some of the observed phenotypes could be the result of the lack a functional AR during development. Conversely, a transgenic mouse line has been generated expressing the chloramphenicol acetyltransferase (CAT) reporter gene under the regulation of probasin, a prostate-specific promoter (Y. Yan et al., Prostate 32:129-139 (1997)). This and related lines are useful tools for the assessment of AR function, but they are limited to defining AR function in the prostate.

[0013] Therefore, it would be of interest to develop a transgenic non-human mammalian model for the assessment of tissue specific activity of the androgen receptor. Such a model could be used to study the tissue selective activity of pharmacological agents as well as the activity of the androgen receptor in different organs of males and females. The described invention herein represents such a model using a reporter gene under the control of an androgen-regulated promoter.

SUMMARY OF THE INVENTION

[0014] The present invention provides a transgenic non-human mammal whose genome comprises a nucleic acid construct, wherein said construct comprises a reporter nucleic acid encoding a reporter operably linked to a promoter comprising an androgen response element (ARE), and said construct further comprises an androgen receptor nucleic acid encoding an androgen receptor, and wherein expression of said reporter nucleic acid is regulated by expression of said androgen receptor nucleic acid. In one aspect, the reporter is luciferase. In another aspect, the androgen response element is 2×DR-1.

[0015] The invention also provides a cell isolated from the transgenic mouse of the invention, wherein the genome of said cell comprises said nucleic acid construct.

[0016] The invention also provides a mouse cell line comprising the cell isolated from the transgenic mouse of the invention.

[0017] The invention also provides an isolated nucleic acid construct that comprises a reporter nucleic acid encoding a reporter operably linked to a promoter comprising an androgen response element (ARE), and said construct further comprises an androgen receptor nucleic acid encoding an androgen receptor, and wherein expression of said reporter nucleic acid is regulated by expression of said androgen receptor nucleic acid. In one aspect, the reporter is luciferase. In another aspect, the androgen response element is 2×DR-1.

[0018] The invention also includes a method for obtaining a target mouse whose genome comprises a nucleic acid construct, wherein said construct comprises a reporter nucleic acid encoding a reporter operably linked to a promoter comprising an androgen response element, and said construct further comprises an androgen receptor nucleic acid encoding an androgen receptor, and wherein expression of said reporter nucleic acid is regulated by expression of said androgen receptor nucleic acid, wherein said mouse can be bred to produce progeny mice whose genomes comprise said nucleic acid construct, said method comprising the steps of:

[0019] (a) solating a fertilized egg from a first female mouse;

[0020] (b) transferring a transgene comprising said nucleic acid construct into the fertilized egg;

[0021] (c) transferring the fertilized egg of step (b) to the uterus of a pseudopregnant second female mouse; and

[0022] (d) maintaining said second female mouse such that:

[0023] (i) said second female mouse becomes pregnant with an embryo derived from said fertilized egg of step (c);

[0024] (ii) said embryo develops into said target mouse; and

[0025] (iii) said target mouse is viably born from said second female mouse; wherein the genome of said target mouse comprises said nucleic acid construct and wherein said mouse can be bred to produce progeny mice whose genomes comprise said nucleic acid construct.

[0026] The invention also includes a method for producing a transgenic mouse cell line that expresses a reporter nucleic acid, said method comprising: (a) isolating cells from the transgenic mouse of the invention; and (b) placing the isolated cells under conditions to maintain growth and viability of the isolated cells such that said transgenic mouse cell line expresses said reporter nucleic acid.

[0027] The invention also provides a method of screening for a modulator of the androgen receptor, comprising administering a test substance to a transgenic non-human mammal of the invention and assaying the effect of said test substance on the activity of the androgen receptor. Modulators of the androgen receptor are particularly useful for treating a disorder associated with defective AR function, such as a cancer. In one aspect, the invention provides a method of identifying a test substance which is an antagonist or agonist of an androgen receptor, said method comprising: (a) determining the expression of said reporter in a transgenic mouse of the invention; (b) administering said test substance to a transgenic mouse of the invention and determining the expression of said reporter following said administering; (c) comparing the expression of said reporter in said step (a) and said step (b); wherein an increase in the expression of said reporter in said step (b) identifies said test substance as an agonist of said androgen receptor and wherein a decrease in the expression of said reporter is said step (b) identifies said test substance as an antagonist of said androgen receptor.

[0028] The invention further provides a transgenic non-human mammal whose genome comprises a nucleic acid construct, wherein said construct comprises a reporter nucleic acid encoding a reporter operably linked to a promoter comprising an androgen response element, and said construct further comprises an androgen receptor nucleic acid encoding an androgen receptor, and wherein said non-human mammal expresses said reporter nucleic acid in organs when said androgen receptor nucleic acid is expressed. Thus, expression of said reporter nucleic acid is regulated by expression of said androgen receptor nucleic acid.

[0029] The invention comprises a transgenic non-human mammal whose germ cells and somatic cells express a reporter gene under the regulation of a promoter capable of expressing androgen receptor, i.e., under the regulation of androgen response elements, and wherein said non-human mammal expresses luciferase in organs where the androgen receptor is activated. Cells in which the androgen receptor was activated can be readily determined by the expression of the reporter gene, which can be measured by standard bioluminescence imaging techniques known to those skilled in the art. In a preferred embodiment of the invention the non-human mammal is a mouse and the transgene construct comprises a reporter gene, comprising luciferase cDNA (SEQ ID NO: 2) regulated by a promoter containing two copies of the androgen response element DR-1 (2×DR-1) (SEQ ID NO: 3) and rat androgen receptor cDNA (SEQ ID NO: 4) regulated by the CMV promoter (SEQ ID NO: 5). The invention further comprises non-human mammalian embryos carrying the androgen-regulated reporter gene capable of developing into viable transgenic animals whose progeny carry the androgen-regulated reporter gene after breeding forward by sexual reproduction. The invention further comprises DNA constructs comprising selected promoters plus the reporter gene and the rat AR cDNA or DNA segments cloned into plasmids for ultimate insertion into the genome of a mammal.

[0030] The transgenic non-human mammals of the invention are characterized by the emission of light in tissues that contain an active androgen receptor. In a preferred embodiment of the invention the transgenic non-human mammals are utilized as a model or surrogate for human AR function for the identification and optimization of molecules and compounds that modulate androgen receptor activity. Molecules and compounds so identified can be used in the prevention and treatment of disorders associated with defective AR function including, but not limited to prostate cancer and andropausia. Thus, the invention provides an in vivo system to monitor the activity of the androgen receptor in different organs and tissues.

[0031] A further object of the present invention is to provide methods for identifying selective androgen receptor modulators (SARMs) that can act as antagonists or agonists in different tissues containing the androgen receptor. In one embodiment, antagonist activity in hormone-dependent tumors is ascertained via screening for inhibition of growth, either in vitro or in vivo, in hormone-dependent tumor cell lines. In another embodiment, the activity of potential SARM is also assessed in normal, non-tumor cell lines. Alternatively, an animal model expressing a hormone-dependent reporter gene can be used to assess the activity of a potential SARM in different tissues in the animal. Thus, the invention also embodies non-human mammals and methods for the identification of selective modulators of the androgen receptor and pharmaceutical compositions comprising the selective modulators so identified.

BRIEF DESCRIPTION OF THE DRAWINGS:

[0032]FIG. 1 shows a diagrammatic representation of the transgene ARELUC/CMV-rAR construct (SEQ ID NO: 1). The luciferase cDNA (SEQ ID NO: 2) was cloned into a vector downstream of a promoter containing two androgen regulated elements (ARE-DR-1) and the SV40 promoter (SEQ ID NO: 3) and was flanked with intron and polyA sequences for efficient message processing. The rat androgen receptor cDNA (SEQ ID NO: 4) was cloned into the same plasmid downstream of the CMV promoter (SEQ ID NO: 5).

[0033] FIGS. 2A-2D show the nucleotide sequence of the ARE-LUC/CMV-rAR transgenic construct (SEQ ID NO: 1).

[0034]FIG. 3 shows the nucleotide sequence of the luciferase cDNA (SEQ ID NO: 2) The numbering corresponds to the position in the ARE-LUC/CMV-rAR construct (SEQ ID NO: 1)

[0035]FIG. 4 shows the nucleotide sequence of the 2×DR-1 SV40 promoter (SEQ ID NO: 3). The numbering corresponds to the position in the ARE-LUC/CMV-rAR construct (SEQ ID NO: 1).

[0036]FIG. 5 shows the nucleotide sequence of the rat androgen receptor cDNA (SEQ ID NO: 4). The numbering corresponds to the position in the ARE-LUC/CMVrAR construct (SEQ ID NO: 1).

[0037]FIG. 6 shows the nucleotide sequence of the CMV promoter (SEQ ID NO: 5). The numbering corresponds to the position in the ARE-LUC/CMV-rAR construct (SEQ ID NO: 1)

[0038]FIG. 7 shows a representative Northern blot analysis of the lung, heart, liver, and testis tissues of a control and three progeny mice found to have passed the transgene (ARE-LUC/CMV-rAR). Each lane contains 20 μg of total RNA isolated from the respective tissues resolved on a 1% agarose gel in 17.5% formaldehyde.

[0039]FIG. 8A shows a representative set of line 26 mice, one control and two transgenic mice, 15 minutes after being subcutaneously injected with 150 mg/kg of luciferin anesthetized, and placed in the Xenogen imaging system. Luciferase light emission was detected with a cooled CCD IVIS™ camera and represents the organs containing an active androgen receptor that induced the expression of the enzyme. FIG. 8B shows the same animals one week after the control and one of the transgenic mice (left and middle mouse, respectively) were castrated.

[0040]FIG. 9 shows the image captured with the charge-coupled device (CDD) IVIS™ camera (Xenogen Corporation, Alameda, Calif.) of the testis isolated from the transgenic mouse described in the FIG. 8A and the respective control.

[0041] FIGS. 10A-D show representative light emission pictures of control non-transgenic and transgenic pairs of mice from line 26 twenty four hours after being treated with testosterone (2 mg/kg).

[0042]FIG. 11 shows the luciferase activity measured in the different organ extracts from transgenic or non-transgenic mice treated or not treated with testosterone. Equal amounts of protein were assayed for the different groups.

[0043]FIG. 12 shows the effect of an androgen receptor antagonist, bicalutamide, (Casodex®, Astra Zeneca, London, UK) on the testosterone induced luciferase activity in quadriceps, bone, prostate/ seminal vesicles and kidney. Luciferase activity (cps) was measured in duplicates in equivalent protein samples (100 μg) of the corresponding organ extracts. The results are the average of three animals per group.

DETAILED DESCRIPTION OF THE INVENTION

[0044] The androgen receptor is a hormone regulated transcription factor that controls the expression of many genetic programs involved in normal physiological processes, i.e., male sexual differentiation, as well as in pathological conditions such as prostate cancer. Those activities of the androgen receptor are cell type specific and depend on a number of cofactors that coexist in each one of those cell types.

[0045] The invention relates to the production of transgenic non-human mammals containing within their genomes a reporter gene, such as a luciferase reporter gene, whose expression is regulated by an activated androgen receptor, as well as an engineered vector designed to express functional androgen receptor. Upon injection of luciferin, luciferase's substrate from fireflies, the animals emit light from the tissues where the enzyme luciferase is produced, indicating activity of either the engineered or endogenous androgen receptor.

[0046] In a preferred embodiment of the invention, the reporter gene is luciferase, but those skilled in the art would know how to select and use other reporter genes including, but not limited to, green fluorescent protein (GFP), beta-galactosidase, beta-lactamase, chloramphemicol acetyltransferase (CAT), dopamine 2 receptor (D2R), thymidine kinase (TK), alkaline phosphatase (AP) or a generic tag detectable by ELISA. In the preferred embodiment, luciferase is used in the Ivis™ Imaging System (Xeragon Corporation, Alameda, Calif.).

[0047] Provided herein is the establishment of transgenic lines that express luciferase cDNA under the control of a promoter containing two direct repeat-1 androgen response elements (2×DR-1 AREs) (SEQ ID NO: 3) and rat androgen receptor cDNA (SEQ ID NO: 4) under the control of the cytomegalovirus (CMV) promoter (SEQ ID NO: 5). DR-1 is an 11-base pair sequence (5′ GGAACGGAACA 3′) (SEQ ID NO: 6), consisting of two potential core binding sites oriented as an overlapping direct repeat. DR-1 was identified as a potent androgen response element (ARE) by the binding of a human AR DNA-binding domain fusion protein to DNA in a random sequence selection assay (Z. Zhou et al., J. Biol. Chem., 272:8227-8235 (1997)). The placement in tandem of two copies of DR-1 demonstrated a strong preference for AR binding and transactivation when compared with the glucocorticoid receptor (Id.). Lines of mice were generated that expressed the transgene in multiple organs including, lung, heart, liver, and testis; mice harboring the transgene did not develop any abnormality. The transgenic animals described herein can be utilized in the identification, development, and optimization of biological and chemical moieties that modulate the activity of the androgen receptor. Such moieties in turn can be used for the treatment of, but not limited to, prostate cancer, andropausia, and hormone replacement.

[0048] A construct was generated in which luciferase cDNA (SEQ ID NO: 2) from the pGL3 vector (Promega Corporation, Madison, Wis.) was placed under the regulation of a promoter containing two DR-1 AREs (SEQ ID NO: 3) (Z. Zhou et al., J. Biol. Chem., 272:8227-8235 (1997)) and was flanked with the chicken beta-globin intron and polyA sequences for efficient message processing. One skilled in the art would be able to select and use other AREs, in addition to DR-1, for use in regulatory luciferase expression. Separated by a stop transcription cassette, the same vector contains in an opposite orientation the CMV promoter (SEQ ID NO: 5) regulating the expression of the rat androgen receptor cDNA (SEQ ID NO: 4) as well as the SV40 virus intron and polyA sequences for efficient message processing (FIG. 1). The CMV promoter (SEQ ID NO: 5), when expressed in vivo in an animal, drives transcription of downstream sequences ubiquitously, in nearly every tissue. One skilled in the art would be able to clone the transgene of the invention into a vector under the control of other tissue specific promoters.

[0049] In a preferred embodiment described in the examples that follow the construct contained the engineered luciferase gene under the control of a promoter regulated by the androgen receptor (FIGS. 2A-2D, SEQ ID NO: 1). Those skilled in the art will recognize that other constructs can be generated that will be useful for the characterization of other members of the steroid nuclear hormone receptor family, such as the glucocorticoid, progesterone, mineralocorticoid, and estrogen receptors. By way of example, and not intending to be limited thereto, the transgene of the invention may comprise a promoter containing DR-1 androgen response elements, but other AREs, such as C3, PSA-AREs or probasin-AREs, or promoters containing glucocorticoid response elements, progesterone response elements, mineralocorticoid response elements or estradiol response elements.

[0050] The nucleotide sequences (cDNA) used herein were cloned using standard molecular biology techniques (Maniatus et al., Molecular Cloning: A Laboratory Manual, Cold Spring Harbor Laboratory (1982); Ausubel et al., Current Protocols in Molecular Biology, John Wiley and Sons, Volume 2 (1991)) based on sequences available in the public domain (e.g., GenBank).

[0051] The construct may also comprise selected nucleic acid regions associated with the transgene (as by fusion therewith) for mediation of, for example, its introduction into the target genome, its expression loci in the transgenic mammal, on/off external regulation of transgene expression, and other desired features, as generally known in the art.

[0052] Microinjection of the above identified DNA construct into the pronucleus of fertilized oocytes resulted in the generation of four founder mice carrying the transgene (ARLuc) DNA. Of these four mice, three were found to pass the transgene in a Mendelian fashion to offspring. Mice from these three lines were subsequently examined for expression of the luciferase gene in multiple tissues. As can be seen in FIG. 7, one transgenic mouse line, identified as Line 26, had particularly high levels of the androgen responsive luciferase transgene expression in the lung, heart, and testis.

[0053] Three male transgenic mice from the line 26, one non-transgenic and two transgenic, were injected at 39 days old with 150 mg/kg body weight of luciferin 15 minutes prior to been anesthetized and placed in an IVIS™ Imaging System (Xenogen Corporate, Alameda, Calif.) where luciferase is detected with a cooled charge-coupled device (CCD) IVIS™ camera (Xenogen, Alameda, Calif.) and the images captured with Living Image® Software (Xenogen, Alameda, Calif.) designed by the manufacturer. As shown in FIGS. 8A and B, in contrast to the non-transgenic control, both transgenic mice present luminescence indicating luciferase expression predominantly in the genital area. In order to confirm that this expression was androgen dependent, the same study was repeated on the same animals one week after one of the transgenic mice was castrated. FIG. 8B shows the loss of luminescence in the castrated mouse, confirming the androgen dependent expression of the luciferase.

[0054] Without wishing to be bound by any theory, it was believed that the high luminescence observed in the genital area was due to the fact that the testis are the organs where androgens are synthesized and therefore the activity of the androgen receptor should be maximal. In order to test this belief, the testis from a control and transgenic mice were isolated after the animals were injected with 150 mg/kg luciferin, and exposed to the camera. As shown in FIG. 9, in contrast to the testes isolated from the non-transgenic animal, the testes from the transgenic animal emitted substantial light, which further confirms the androgen dependent regulation of the luciferase expression.

[0055] To further prove the effect of androgens on the expression of luciferase, two pairs of mice from line 26 were imaged at day 0 and at day 1 after receiving a subcutaneous injection of 2 mg/kg testosterone. As shown in FIGS. 10A-10D, testosterone treatment increased the total photon emission between 1.5 and 3.7 fold (comparing transgenic mice tag #454 and tag #453 with their baseline before treatment). The ratios for treated animals as compared to their non-transgenic controls were 16.2 and 29.0 folds, respectively.

[0056] In order to test first, the possibility of measuring luciferase activity in single organs, and second, the ability to detect differences in the androgen function among them, luciferase activity was measured from total extracts prepared from brain, lung, liver, quadriceps, seminal vesicles, and heart. As shown in FIG. 11, testosterone treatment of transgenic mice promoted an increase in luciferase activity in brain (3.4 fold), quadriceps (7.2 fold), seminal vesicles (4.2 fold), and heart (3.8 fold) with respect to the extracts from their corresponding non-transgenic control.

[0057] The transgenic animals of the invention are also useful for the development of compounds or pharmacotherapies for the treatment of disorders associated with defective androgen receptor function, particularly cancer. By “defective androgen receptor function” is meant any function resulting from aberrant expression, that is, either in an up-regulated or down-regulated manner, relevant to that of the wild type androgen receptor. To demonstrate this utility, three groups of mice were treated with testosterone (2 mg/kg, s.c.), testosterone and Casodex® (50 mg/kg, p.o.), or untreated, respectively. As shown in FIG. 12, bicalutamide (Casodex®) inhibited testosterone induced luciferase expression in quadriceps, bone, prostate-seminal vesicles with an acceptable dynamic range (92% inhibition of the testosterone effect (5.8 fold induction over untreated) in quadriceps, 86% inhibition of the testosterone effect (3.3 fold induction over untreated) in bone, and 90% inhibition of the testosterone effect (5.6 fold induction over untreated) in prostate-seminal vesicles). No response was observed in kidney.

[0058] Having now generally described the invention, the same will be more readily understood through reference to the following examples, which are provided by way of illustration and are not intended to be limiting of the present invention. EXAMPLES:

[0059] 1. ARE-LUC/CMV-rAR Transgene Construct

[0060] A. pGL3/2×DR-1 Luciferase

[0061] Equimolar amounts of the complementary oligonucleotides DR-1(F) (ARE) (SEQ ID NO: 7) and DR-1(R) (ARE) (SEQ ID NO: 8) were annealed and then ligated into the XhoI digested pGL3-Promoter plasmid (Promega Corporation, Madison, Wis.). The oligonucleotide DR-1 (F) (ARE) (SEQ ID NO: 7) has the sequence: 5′TCGAGTCCTGAAGGAACGGAACAGACTGA-3′. The oligonucleotide DR-1(R) (ARE) has the sequence: 5′-TCGATCAGTCTGTTCCGTTCCTTCAGGAC-3′ (SEQ ID NO: 8). A second DR-1 response element was inserted upstream of the existing DR-1 element in pGL3/1×DR-1/luciferase by annealing equimolar amounts of the complementary oligonucleotide 1×DR-1(F) (SEQ ID NO: 9) and 1×DR-1(R) (SEQ ID NO: 10) and then ligating both into the SacI/XhoI digested pGL3/1×DR1/luciferase plasmid. The oligonucleotide 1×DR-1(F) (SEQ ID NO: 9) has the sequence:

[0062] 5′-CGTCCTGAAGGAACGGAACAGACTGA-3′. The oligonucleotide 1×DR-1(R) (SEQ ID NO: 10) has the sequence: 5′-TCGATCAGTCTGTTCCGTTTTTCCTTCAGGACGAGCT-3′.

[0063] B. ARE-LUC/CMV-rAR

[0064] The generation of the expression construct was done using standard molecular biology techniques, for example, Ausubel et al., Current Protocols in Molecular Biology, John Wiley and Sons, Volume 2 (1991). The complete sequence of ARE-LUC/CMV-rAR transgene construct (SEQ NO: 1) is shown in the FIGS. 2A-2D.

[0065] A NotI fragment comprising the nucleotide sequence of SEQ ID NO: 4 and encoding the complete amino acid sequence of the rat androgen receptor was isolated from pcDNA-rAR and blunted using Klenow. The fragment was then cloned into Smal/Afel restricted pCMV-TSIR to create the intermediate pCMV-rARtemp. The plasmid pTetInd was restricted with NotI and BglII, blunted with Klenow, and ligated upon itself. The resulting plasmid was subsequently digested with EcoRV and XbaI and used as a vector for subcloning of the EcoICRI/XbaI fragment isolated following digestion of pGL3-pro/2×DR-1. This fragment comprised an androgen responsive promoter, which was generated by fusing two androgen response elements to the 5-prime end of a minimal SV40 promoter (SEQ ID NO: 3), as well as sequences encoding the full length luciferase protein (SEQ ID NO: 2). The resulting plasmid was designated p2×DR-1-Luctemp-1. A stop transcription cassette flanked by an XhoI site at the 5′ end and a SalI site at the 3′ end was generated by PCR using pBS302 as a template. The XhoI/SalI restricted PCR fragment was subcloned into XhoI restricted p2×DR-1-LucTemp 1 in the orientation such that the 3′ end of the stop cassette was inserted just upstream of the 5′ end of the androgen responsive promoter. The resulting plasmid was designated p2×DR-1-Luctemp-2. This plasmid was then digested with XhoI and XbaI and the fragment containing the stop transcription cassette, androgen responsive promoter, and the sequences encoding the luciferase protein was inserted into XhoI/XbaI restricted pCMV-ARtemp. This resulted in completion of the ARE-LUC/CMV-rAR plasmid. The 8.6 kb DNA fragment generated by PmeI/PacI digestion of ARE-LUC/CMV-rAR was isolated for microinjection into mouse embryos in order to create the ARLuc transgenic animals.

[0066] 2. Generation and Breeding of Transgenic Mice

[0067] Transgenic mice harboring the ARE-LUC/CMV-rAR construct were generated by microinjection of a PmeI/PacI fragment from the above construct into the pronucleus of C57B1/6×DBA2 F2 (B6D2F2) embryos. Embryos were generated by in-house mating of hybrid stud B6D2 males to virgin females from the same background (Harlan Sprague Dawley, Indianapolis, Ind.) using the techniques described by Hogan et al., Manipulating the Mouse Embryo: a Laboratory Manual, second edition, Brigid Hogan, Rosa Beddington, Frank Constantini, and Elizabeth Lacey, eds, Cold Spring Harbor Laboratory Press (1994). Injected embryos were transferred to pseudopregnant ICR female mice (Harlan Sprague Dawley, Indianapolis, Ind.) and allowed to develop to term. At five to eight days of age toe and tail samples were taken for DNA analysis of the transgene. Mice harboring the transgene were identified by a polyrnerase chain reaction (PCR) strategy designed to detect the insulator stop cassette sequences intervening between the CMV promoter and the DR-I sequences in the vector, upstream primer 5′ CTTGGCTTGCTTTGCTATTTA3′ (SEQ NO: 11) and downstream primer 5′ATGTGGTATGGCTGATTATGA3′ (SEQ NO: 12). Founder mice (F0) shown to harbor the transgene were then outbred to the ICR background, and progeny (F1) were again tested for transmission of the transgene in a Mendelian fashion. All mice were housed in shoebox housing with food and water ad lib on a 12/12 light dark cycle, and were humanely handled under the guidelines of the institutional ACUC in an AAALAC accredited facility.

[0068] 3. Gene Expression Analysis

[0069] Detection of ARE-LUC/CMV-rAR transgene expression was performed by Northern blot analysis. To identify transgenic lines that had expression of the transgene, F1 offspring from founders were euthanized and their lung, heart, liver, and testis were harvested. The samples were flash frozen in liquid nitrogen and stored until the time of mRNA isolation. Total RNA was isolated using a monophasic solution of phenol and guanidine isothiocyanates, such as the Trizol® LS Reagent system as described by the manufacturer (GIBCO™ Invitrogen Corporation, Carlsbad, Calif.). From these RNA isolates, MRNA was extracted using the Oligotex Direct mRNA kit as recommended by the manufacturer (Operon/QIAGEN, Valencia, Calif.). The mRNA was resolved in 1.0% agarose gel electrophoresis under denaturing conditions with 17.6% formaldehyde and transferred to nylon membrane (Hybond-N, Amersham Biosciences, Uppsala, Sweden) by capillary blotting before hybridization. ARE-LUC/CMV-rAR messages were detected by hybridizing the RNA to a 607 bp radiolabelled probe designed to detect the luciferase mRNA (Ready-to-Go kit, New England Nuclear/Perkin Elmer™ Life Sciences, Boston, Mass.). The 607 bp fragment was generated by PCR using the pGL3 vector as template and the oligonucleotides LUC (F): 5′-GGTAACCCAGTAGATCCAGAG-3′ (SEQ ID NO: 13) and LUC (R): 5′-GGAAGACGCCAAAAACATAAAG-3′ (SEQ ID NO: 14). Hybridization was done in Rapid-hyb buffer (Amersham Biosciences, Uppsala, Sweden) overnight and nonspecific annealing of the probe was eliminated by multiple washes under stringent conditions (2×20 min in 0.1×SSC, 2%SDS at 65° C.). Specific hybridization of the probe to the luciferase message was detected on a phosphoimager (Model FLA-2000, Mfr. Fuji Film, Stanford, Conn.).

[0070] 4. Luciferase Imaging in Vivo

[0071] Mice designated for detection of luciferase expression by in vivo imaging are injected with 150 mg/kg luciferin in PBS 15 minutes prior to imaging. Subsequently, the mice are placed under chemical restraint by injection with avertin (0.3 ml of a 2.5% solution in PBS). Anesthetized mice are placed in the IVIS™ Imaging System (Xenogen Corporation, Alameda, Calif.), a dark box containing a cooled CCD IVIS™ camera and stage. After image acquisition of two minutes, the images are processed with Living Image® Software (Xenogen, Alameda, Calif.). For imaging of tissues, the mice are injected with luciferin 15 minutes prior to euthanasia via carbon dioxide, and the tissues excised and imaged accordingly.

[0072] 5. Measurement of Luciferase Activity in Total Organ Extracts.

[0073] Heart, lung, liver, muscle, brain, bone, seminal vesicles (including prostate), and testis were collected and flash frozen until assay time. Extracts were prepared and luciferase activity was assessed using the luciferase assay kit (LUC1-1KT) (Sigma). Tissues were ground to a fine powder by mortar and pestle in the presence of liquid nitrogen and then placed in 1 ml of lysis buffer. Insoluble material was spun out at 14,000 rpm for ten minutes. (Eppendorf microfuge). The top layer of fat was discarded and the supernatant was collected. A Bradford assay (M. Bradford, Anal. Biochem. 1976, 72: 248-254) was done in triplicate to determine protein concentration. One hundred μg of total protein per tissue was added to 100 μl of assay buffer containing the luciferase substrate in triplicate. Chemiluminesence was measured in costar black 96 well plates by a Beckman top count in counts per second.

1 14 1 11004 DNA Artificial artificial nucleic acid construct 1 ccagggccag gtagcctgtg gtgcctctga tgtgggcttg aggagagcca tcctcagggt 60 gctgctgccg ccgccgccgc cgggggctag tctcctgccg ctgctgtaaa caggcaccgg 120 gaggtgctat gctagcggcc tcagggtgcc tggggcccgg gttctggatc gcttcgcgca 180 cgctctggaa cagattctgg aacgctcctc gataggtctt ggacgggggc cgtgggtaga 240 cccttcccag ccctaactgc acctccatcc taatcgaatt cccgcggccg ggaagctagc 300 taggatccaa gaattcgggg ccgcggaggc tggatcggtc ccggtgtctt ctatggaggt 360 caaaacagcg tggatggcgt ctccaggcga tctgacggtt cactaaacga gctctgctta 420 tatagacctc ccaccgtaca cgcctaccgc ccatttgcgt caatggggcg gagttgttac 480 gacattttgg aaagtcccgt tgattttggt gccaaaacaa actcccattg acgtcaatgg 540 ggtggagact tggaaatccc cgtgagtcaa accgctatcc acgcccattg atgtactgcc 600 aaaaccgcat caccatggta atagcgatga ctaatacgta gatgtactgc caagtaggaa 660 agtcccataa ggtcatgtac tgggcataat gccaggcggg ccatttaccg tcattgacgt 720 caataggggg cgtacttggc atatgataca cttgatgtac tgccaagtgg gcagtttacc 780 gtaaatactc cacccattga cgtcaatgga aagtccctat tggcgttact atgggaacat 840 acgtcattat tgacgtcaat gggcgggggt cgttgggcgg tcagccaggc gggccattta 900 ccgtaagtta tgtaacgcgg aactccatat atgggctatg aactaatgac cccgtaattg 960 attactatta ataactagtc aataatcaat gtcaacatgg cggtaatgtt ggacatgagc 1020 caatataaat gtacatatta tgatatggat acaacgtatg caatgggcca agctcctcga 1080 gaatcgcgag gtacagctgc caccgttgtt tccaccgaag aaaccaccgt tgccgtaacc 1140 accacgacgg ttgttgctaa agaagctgcc accgccacgg ccaccgttgt agccgccgtt 1200 gttgttattg tagttgctac tgttatttct ggcacttctt ggttttcctc ttaagtgagg 1260 aggaacataa ccattctcgt tgttgtcgtt gatgcttaaa ttttgcactt gttcgctcag 1320 ttcagccata atatgaaatg cttttcttgt tgttcttacg gaataccact tgccacctat 1380 caccacaact aactttttcc cgttcctcca tctcttttat attttttttc tcgactttta 1440 tatttttttt atcgagggat ctttgtgaag gaaccttact tctgtggtgt gacataattg 1500 gacaaactac ctacagagat ttaaagctct aaggtaaata taaaattttt aagtgtataa 1560 tgtgttaaac tactgattct aattgtttgt gtattttaga ttccaaccta tggaactgat 1620 gaatgggagc agtggtggaa tgcctttaat gaggaaaacc tgttttgctc agaagaaatg 1680 ccatctagtg atgatgaggc tactgctgac tctcaacatt ctactcctcc aaaaaagaag 1740 agaaaggtag aagaccccaa ggactttcct tcagaattgc taagtttttt gagtcatgct 1800 gtgtttagta atagaactct tgcttgcttt gctatttaca ccacaaagga aaaagctgca 1860 ctgctataca agaaaattat ggaaaaatat tctgtaacct ttataagtag gcataacagt 1920 tataatcata acatactgtt ttttcttact ccacacaggc atagagtgtc tgctattaat 1980 aactatgctc aaaaattgtg tacctttagc tttttaattt gtaaaggggt taataaggaa 2040 tatttgatgt atagtgcctt gactagagat cataatcagc cataccacat ttgtagaggt 2100 tttacttgct ttaaaaaacc tcccacacct ccccctgaac ctgaaacata aaatgaatgc 2160 aattgttgtt gttaacttgt ttattgcagc ttataatggt tacaaataaa gcaatagcat 2220 cacaaatttc acaaataaag catttttttc actgcattct agttgtggtt tgtccaaact 2280 catcaatgta tcttatcatg tctggatctg acatggtaag taagctcgac gcggccgatc 2340 ttagatctcg tcctgaagga acggaacaga ctgatcgagt cctgaaggaa cggaacagac 2400 tgatcgagat ctgcgatctg catctcaatt agtcagcaac catagtcccg cccctaactc 2460 cgcccatccc gcccctaact ccgcccagtt ccgcccattc tccgccccat cgctgactaa 2520 ttttttttat ttatgcagag gccgaggccg cctcggcctc tgagctattc cagaagtagt 2580 gaggaggctt ttttggaggc ctaggctttt gcaaaaagct tggcattccg gtactgttgg 2640 taaagccacc atggaagacg ccaaaaacat aaagaaaggc ccggcgccat tctatccgct 2700 ggaagatgga accgctggag agcaactgca taaggctatg aagagatacg ccctggttcc 2760 tggaacaatt gcttttacag atgcacatat cgaggtggac atcacttacg ctgagtactt 2820 cgaaatgtcc gttcggttgg cagaagctat gaaacgatat gggctgaata caaatcacag 2880 aatcgtcgta tgcagtgaaa actctcttca attctttatg ccggtgttgg gcgcgttatt 2940 tatcggagtt gcagttgcgc ccgcgaacga catttataat gaacgtgaat tgctcaacag 3000 tatgggcatt tcgcagccta ccgtggtgtt cgtttccaaa aaggggttgc aaaaaatttt 3060 gaacgtgcaa aaaaagctcc caatcatcca aaaaattatt atcatggatt ctaaaacgga 3120 ttaccaggga tttcagtcga tgtacacgtt cgtcacatct catctacctc ccggttttaa 3180 tgaatacgat tttgtgccag agtccttcga tagggacaag acaattgcac tgatcatgaa 3240 ctcctctgga tctactggtc tgcctaaagg tgtcgctctg cctcatagaa ctgcctgcgt 3300 gagattctcg catgccagag atcctatttt tggcaatcaa atcattccgg atactgcgat 3360 tttaagtgtt gttccattcc atcacggttt tggaatgttt actacactcg gatatttgat 3420 atgtggattt cgagtcgtct taatgtatag atttgaagaa gagctgtttc tgaggagcct 3480 tcaggattac aagattcaaa gtgcgctgct ggtgccaacc ctattctcct tcttcgccaa 3540 aagcactctg attgacaaat acgatttatc taatttacac gaaattgctt ctggtggcgc 3600 tcccctctct aaggaagtcg gggaagcggt tgccaagagg ttccatctgc caggtatcag 3660 gcaaggatat gggctcactg agactacatc agctattctg attacacccg agggggatga 3720 taaaccgggc gcggtcggta aagttgttcc attttttgaa gcgaaggttg tggatctgga 3780 taccgggaaa acgctgggcg ttaatcaaag aggcgaactg tgtgtgagag gtcctatgat 3840 tatgtccggt tatgtaaaca atccggaagc gaccaacgcc ttgattgaca aggatggatg 3900 gctacattct ggagacatag cttactggga cgaagacgaa cacttcttca tcgttgaccg 3960 cctgaagtct ctgattaagt acaaaggcta tcaggtggct cccgctgaat tggaatccat 4020 cttgctccaa caccccaaca tcttcgacgc aggtgtcgca ggtcttcccg acgatgacgc 4080 cggtgaactt cccgccgccg ttgttgtttt ggagcacgga aagacgatga cggaaaaaga 4140 gatcgtggat tacgtcgcca gtcaagtaac aaccgcgaaa aagttgcgcg gaggagttgt 4200 gtttgtggac gaagtaccga aaggtcttac cggaaaactc gacgcaagaa aaatcagaga 4260 gatcctcata aaggccaaga agggcggaaa gatcgccgtg taattctaga gctgagaact 4320 tcagggtgag tttggggacc cttgattgtt ctttcttttt cgctattgta aaattcatgt 4380 tatatggagg gggcaaagtt ttcagggtgt tgtttagaat gggaagatgt cccttgtatc 4440 accatggacc ctcatgataa ttttgtttct ttcactttct actctgttga caaccattgt 4500 ctcctcttat tttcttttca ttttctgtaa ctttttcgtt aaactttagc ttgcatttgt 4560 aacgaatttt taaattcact tttgtttatt tgtcagattg taagtacttt ctctaatcac 4620 ttttttttca aggcaatcag ggtatattat attgtacttc agcacagttt tagagaacaa 4680 ttgttataat taaatgataa ggtagaatat ttctgcatat aaattctggc tggcgtggaa 4740 atattcttat tggtagaaac aactacaccc tggtcatcat cctgcctttc tctttatggt 4800 tacaatgata tacactgttt gagatgagga taaaatactc tgagtccaaa ccgggcccct 4860 ctgctaacca tgttcatgcc ttcttctctt tcctacagct cctgggcaac gtgctggttg 4920 ttgtgctgtc tcatcatttt ggcaaagaat taattcactc ctcaggtgca ggctgcctat 4980 cagaaggtgg tggctggtgt ggccaatgcc ctggctcaca aataccactg agatcgatct 5040 ttttccctct gccaaaaatt atggggacat catgaagccc cttgagcatc tgacttctgg 5100 ctaataaagg aaatttattt tcattgcaat agtgtgttgg aattttttgt gtctctcact 5160 cggaaggatt aattaaggcc gccctatttt tataggttaa tgtcatgata ataatggttt 5220 cttagacgtc aggtggcact tttcggggaa atgtgcgcgg aacccctatt tgtttatttt 5280 tctaaataca ttcaaatatg tatccgctca tgagacaata accctgataa atgcttcaat 5340 aatattgaaa aaggaagagt atgagtattc aacatttccg tgtcgccctt attccctttt 5400 ttgcggcatt ttgccttcct gtttttgctc acccagaaac gctggtgaaa gtaaaagatg 5460 ctgaagatca gttgggtgca cgagtgggtt acatcgaact ggatctcaac agcggtaaga 5520 tccttgagag ttttcgcccc gaagaacgtt ttccaatgat gagcactttt aaagttctgc 5580 tatgtggcgc ggtattatcc cgtgttgacg ccgggcaaga gcaactcggt cgccgcatac 5640 actattctca gaatgacttg gttgagtact caccagtcac agaaaagcat cttacggatg 5700 gcatgacagt aagagaatta tgcagtgctg ccataaccat gagtgataac actgcggcca 5760 acttacttct gacaacgatc ggaggaccga aggagctaac cgcttttttg cacaacatgg 5820 gggatcatgt aactcgcctt gatcgttggg aaccggagct gaatgaagcc ataccaaacg 5880 acgagcgtga caccacgatg cctgtagcaa tggcaacaac gttgcgcaaa ctattaactg 5940 gcgaactact tactctagct tcccggcaac aattaataga ctggatggag gcggataaag 6000 ttgcaggacc acttctgcgc tcggcccttc cggctggctg gtttattgct gataaatctg 6060 gagccggtga gcgtgggtct cgcggtatca ttgcagcact ggggccagat ggtaagccct 6120 cccgtatcgt agttatctac acgacgggga gtcaggcaac tatggatgaa cgaaatagac 6180 agatcgctga gataggtgcc tcactgatta agcattggta actgtcagac caagtttact 6240 catatatact ttagattgat ttaaaacttc atttttaatt taaaaggatc taggtgaaga 6300 tcctttttga taatctcatg accaaaatcc cttaacgtga gttttcgttc cactgagcgt 6360 cagaccccgt agaaaagatc aaaggatctt cttgagatcc tttttttctg cgcgtaatct 6420 gctgcttgca aacaaaaaaa ccaccgctac cagcggtggt ttgtttgccg gatcaagagc 6480 taccaactct ttttccgaag gtaactggct tcagcagagc gcagatacca aatactgttc 6540 ttctagtgta gccgtagtta ggccaccact tcaagaactc tgtagcaccg cctacatacc 6600 tcgctctgct aatcctgtta ccagtggctg ctgccagtgg cgataagtcg tgtcttaccg 6660 ggttggactc aagacgatag ttaccggata aggcgcagcg gtcgggctga acggggggtt 6720 cgtgcacaca gcccagcttg gagcgaacga cctacaccga actgagatac ctacagcgtg 6780 agctatgaga aagcgccacg cttcccgaag ggagaaaggc ggacaggtat ccggtaagcg 6840 gcagggtcgg aacaggagag cgcacgaggg agcttccagg gggaaacgcc tggtatcttt 6900 atagtcctgt cgggtttcgc cacctctgac ttgagcgtcg atttttgtga tgctcgtcag 6960 gggggcggag cctatggaaa aacgccagca acgcggcctt tttacggttc ctggcctttt 7020 gctggccttt tgctcacatg ttctttcctg cgttatcccc tgattctgtg gataaccgta 7080 ttaccgcctt tgagtgagct gataccgctc gccgcagccg aacgaccgag cgcagcgagt 7140 cagtgagcga ggaagcggaa gagcgcccaa tacgcaaacc gcctctcccc gcgcgttggc 7200 cgattcatta atgcagctga acggtctggt tataggtaca ttgagcaact gactgaaatg 7260 cctcaaaatg ttctttacga tgccattggg atatatcaac ggtggtatat ccagtgattt 7320 ttttctccat tttagcttcc ttagctcctg aaaatctcgc caagcttggt cgagctggat 7380 acttcccgtc cgccaggggg acatgccggc gatgctgaag gtcgcgcgca ttcccgatga 7440 agaggccggt aacagagctc ggcgcgccgt ttaaaccaga cataagatac attgatgagt 7500 ttggacaaac cacaactaga atgcagtgaa aaaaatgctt tatttgtgaa atttgtgatg 7560 ctattgcttt atttgtaacc attataagcg gcaataaaca agttaacaac aacaattgca 7620 ttcattttat gtttcaggtt cagggggagg tgtgggaggt tttttaaagc aagtaaaacc 7680 tctacaaatg tggtatggct gattatgatc tctagtcaag gcactataca tcaaatattc 7740 cttattaacc cctttacaaa ttaaaaagct aaaggtacac aatttttgag catagttatt 7800 aatagcagac actctatgcc tgtgtggagt aagaaaaaac agtatgttct gattataact 7860 gttatgccta cttataaagg ttacagaata tttttccata attttcttgt atagcagtgc 7920 agctttttcc tttgtggtgt aaatagcaaa gcaagcaaga gttctattac taaacacagc 7980 atgactcaaa aaacttagca attctgaagg aaagtccttg gggtcttcta cctttctctt 8040 cttttttgga ggagtagaat gttgagagtc agcagtagcc tcatcatcac tagatggcat 8100 ttcttctgag caaaacaggt tttcctcatt aaaggcattc caccactgct cccattcatc 8160 agttccatag gttggaatct aaaatacaca aacaattaga atcagtagtt taacacatta 8220 tacacttaaa aattttatat ttaccttaga gctttaaatc tctgtaggta gtttgtccaa 8280 ttatgtcaca ccacagaagt aaggttcctt cacaaagatc ctctgtacat caagatccgc 8340 tttcacattt cagctgtttt tccagtccgc agatgatcag ttccaggccg aacaggaagg 8400 ctggctctgc accctggtga tcaaacagtt cgatagcctg gcgcagcaga ggaggcatgc 8460 tatcagtagt aggtgtttcc ctttcttctt tagcgacctg atgctcctga tcttccagca 8520 cgcaacccag agtaaaatgt cccacagcgg ccgcgggaat tcgatttcac tgtgtgtgga 8580 aatagatggg cttgactttc ccagaaagga tcttgggcac ttgcacagag atgatctctg 8640 ccatcatttc aggaaagtcc acgctcacca tatgggactt gattagcagg tcaaaagtga 8700 attgatgcag ctctcttgca ataggctgca cagaatccag gagcttggtg agctggtaga 8760 agcgccttga gcaggatgtg ggattttttc ttttgcatgc aatgatgcga tcaagttcct 8820 tgatgtagtt cattcgaagt tcatcaaaga atttttgatt tttcagccca tccactggaa 8880 taatgctgaa gagtagcagt gctttcatgc acaggaattc ctggggggtt atctggagcc 8940 atccaaactc ttgagaaagg tgcctcatcc tcacgcactg gctgtacatt cgagacttgt 9000 gcatgcgata ctcattgaaa accaggtcag gtgcaaagta gagcatccta gagttgacat 9060 tagtgaagga ccgccaaccc atggcaaata ccatcagtcc catccaggaa tactgaatga 9120 ctgccatctg gtcatccaca tgcaagttgc ggaagccagg caaggccttg gcccacttga 9180 ccacatgtac aagctgtctc tcgccaagct cgttgagact agataacaag gcagcaaagg 9240 aatcaggctg gttgttgtca tgtccggcac acaccactcc tggctcaatg gcttccagga 9300 cattaagaaa gataggttga cattcatagc cttcaatgtg tgatacagtc atcttctggg 9360 atgggtcctc agtggggcta ccagcactgg agttttctcc ttcttcctgt agtttgagat 9420 ttccaagttt cttcagctta cgagctccca gagtcatccc tgcttcataa catttccgga 9480 gacgacacga tggacaattt ttcctccgaa atttatcaat ggtgcaatca tttctgctgg 9540 cacatagata cttctgtttc ccttccgcag ctcttttgaa gaagaccttg cagctgccac 9600 aagtgagagc tccgtagtga caaccagaag cttcatctcc acagatcagg caggtcttct 9660 ggggtgggaa gtaatagtcg atgggtaaaa cgtggtccct ggtactgtcc aaacgcatgt 9720 ccccataagg tccggagtag ttctccatcc aaggtcccat ttcactttta acacaactgg 9780 gactgggata ggggactctg ttcacaactc cgccaggata ccacacttca gaggcagaga 9840 agtcaccctc ctggcttgcc agcccctgag ggggccgagt gtagccatag ggggctacag 9900 gcccagcatc gcttgggcta ctgctgccgc ccccgcctcc tggcccatat aattggcctt 9960 cttcagctgt gaagagagta tgccaggaag aagaggcggt ggctgggggc gatccagtgc 10020 tgggtccggc tacactccct ccatgtaggc tagccaagtc cccatagcgg cattgcgctg 10080 ccgccgcagc ccaggcgctg ccgtagtcca acgggttctc cagcttgatg cgggcgtgtg 10140 gatgggtagg gggcgggggg tgcggcggcc cggacagagc gagcggaaag ttgtagtagt 10200 cgcgattctg gtatgctgct gcctcgtcta ctgctccaga cttatacaga gacagtgagg 10260 acgggatctc aagtgtccca gagctacctg cttcactgct gccagagcag cccagactct 10320 caccttccaa ccctttggcg taacctccct tgaaagagga atactcagca gtctcttcag 10380 tgcctttgcc cgggccttcg tccagggaaa gacctttgca ttcggccaga ggcgcacaag 10440 gagtgggacg cacggcgggt ggacctccca ggagcgacgc gtacatgcag tcgccccgaa 10500 gctgctcccc tggactcaga tgttccagtg cttccacacc caaccccatg gacacagaca 10560 ctgctttaca caactccttg gcactgtcag atatggtcga attgccccct aggtaactat 10620 ccttggagga agagggagcc ccagtggcct cccttgctct cacgctgctg ctgccttcgg 10680 atattacctc ctgctgctgt tgctgctgct gctgctgctg ctgctgctgc tgttgctgtt 10740 gctgctgctg ctgaagaagt tgcatggtgc cggcctcgct caggatgtct ttaatgtctg 10800 cggagcagct gcttaagcct gggaaagtgg ggcccagtag ggacaacgtg gatggggcag 10860 ctgagtcatc ctgatctgga ggagctggtg gctgctgcgg cagccccttg ccaggagccg 10920 tggcagctcc aggctccggg aggcaaaaac tctcagggtg gccctcggag gctgactgct 10980 gctgtgaagg ctgctgttcc tcct 11004 2 1653 DNA Artificial luciferase 2 atggaagacg ccaaaaacat aaagaaaggc ccggcgccat tctatccgct ggaagatgga 60 accgctggag agcaactgca taaggctatg aagagatacg ccctggttcc tggaacaatt 120 gcttttacag atgcacatat cgaggtggac atcacttacg ctgagtactt cgaaatgtcc 180 gttcggttgg cagaagctat gaaacgatat gggctgaata caaatcacag aatcgtcgta 240 tgcagtgaaa actctcttca attctttatg ccggtgttgg gcgcgttatt tatcggagtt 300 gcagttgcgc ccgcgaacga catttataat gaacgtgaat tgctcaacag tatgggcatt 360 tcgcagccta ccgtggtgtt cgtttccaaa aaggggttgc aaaaaatttt gaacgtgcaa 420 aaaaagctcc caatcatcca aaaaattatt atcatggatt ctaaaacgga ttaccaggga 480 tttcagtcga tgtacacgtt cgtcacatct catctacctc ccggttttaa tgaatacgat 540 tttgtgccag agtccttcga tagggacaag acaattgcac tgatcatgaa ctcctctgga 600 tctactggtc tgcctaaagg tgtcgctctg cctcatagaa ctgcctgcgt gagattctcg 660 catgccagag atcctatttt tggcaatcaa atcattccgg atactgcgat tttaagtgtt 720 gttccattcc atcacggttt tggaatgttt actacactcg gatatttgat atgtggattt 780 cgagtcgtct taatgtatag atttgaagaa gagctgtttc tgaggagcct tcaggattac 840 aagattcaaa gtgcgctgct ggtgccaacc ctattctcct tcttcgccaa aagcactctg 900 attgacaaat acgatttatc taatttacac gaaattgctt ctggtggcgc tcccctctct 960 aaggaagtcg gggaagcggt tgccaagagg ttccatctgc caggtatcag gcaaggatat 1020 gggctcactg agactacatc agctattctg attacacccg agggggatga taaaccgggc 1080 gcggtcggta aagttgttcc attttttgaa gcgaaggttg tggatctgga taccgggaaa 1140 acgctgggcg ttaatcaaag aggcgaactg tgtgtgagag gtcctatgat tatgtccggt 1200 tatgtaaaca atccggaagc gaccaacgcc ttgattgaca aggatggatg gctacattct 1260 ggagacatag cttactggga cgaagacgaa cacttcttca tcgttgaccg cctgaagtct 1320 ctgattaagt acaaaggcta tcaggtggct cccgctgaat tggaatccat cttgctccaa 1380 caccccaaca tcttcgacgc aggtgtcgca ggtcttcccg acgatgacgc cggtgaactt 1440 cccgccgccg ttgttgtttt ggagcacgga aagacgatga cggaaaaaga gatcgtggat 1500 tacgtcgcca gtcaagtaac aaccgcgaaa aagttgcgcg gaggagttgt gtttgtggac 1560 gaagtaccga aaggtcttac cggaaaactc gacgcaagaa aaatcagaga gatcctcata 1620 aaggccaaga agggcggaaa gatcgccgtg taa 1653 3 272 DNA Artificial 2XDR-1 and SV40 promoter 3 gatctcgtcc tgaaggaacg gaacagactg atcgagtcct gaaggaacgg aacagactga 60 tcgagatctg cgatctgcat ctcaattagt cagcaaccat agtcccgccc ctaactccgc 120 ccatcccgcc cctaactccg cccagttccg cccattctcc gccccatcgc tgactaattt 180 tttttattta tgcagaggcc gaggccgcct cggcctctga gctattccag aagtagtgag 240 gaggcttttt tggaggccta ggcttttgca aa 272 4 2706 DNA Rattus norvegicus 4 atggaggtgc agttagggct gggaagggtc tacccacggc ccccgtccaa gacctatcga 60 ggagcgttcc agaatctgtt ccagagcgtg cgcgaagcga tccagaaccc gggccccagg 120 caccctgagg ccgctagcat agcacctccc ggtgcctgtt tacagcagcg gcaggagact 180 agcccccggc ggcggcggcg gcagcagcac cctgaggatg gctctcctca agcccacatc 240 agaggcacca caggctacct ggccctggag gaggaacagc agccttcaca gcagcagtca 300 gcctccgagg gccaccctga gagtttttgc ctcccggagc ctggagctgc cacggctcct 360 ggcaaggggc tgccgcagca gccaccagct cctccagatc aggatgactc agctgcccca 420 tccacgttgt ccctactggg ccccactttc ccaggcttaa gcagctgctc cgcagacatt 480 aaagacatcc tgagcgaggc cggcaccatg caacttcttc agcagcagca gcaacagcaa 540 cagcagcagc agcagcagca gcagcagcag caacagcagc aggaggtaat atccgaaggc 600 agcagcagcg tgagagcaag ggaggccact ggggctccct cttcctccaa ggatagttac 660 ctagggggca attcgaccat atctgacagt gccaaggagt tgtgtaaagc agtgtctgtg 720 tccatggggt tgggtgtgga agcactggaa catctgagtc caggggagca gcttcggggc 780 gactgcatgt acgcgtcgct cctgggaggt ccacccgccg tgcgtcccac tccttgtgcg 840 cctctggccg aatgcaaagg tctttccctg gacgaaggcc cgggcaaagg cactgaagag 900 actgctgagt attcctcttt caagggaggt tacgccaaag ggttggaagg tgagagtctg 960 ggctgctctg gcagcagtga agcaggtagc tctgggacac ttgagatccc gtcctcactg 1020 tctctgtata agtctggagc agtagacgag gcagcagcat accagaatcg cgactactac 1080 aactttccgc tcgctctgtc cgggccgccg caccccccgc cccctaccca tccacacgcc 1140 cgcatcaagc tggagaaccc gttggactac ggcagcgcct gggctgcggc ggcagcgcaa 1200 tgccgctatg gggacttggc tagcctacat ggagggagtg tagccggacc cagcactgga 1260 tcgcccccag ccaccgcctc ttcttcctgg catactctct tcacagctga agaaggccaa 1320 ttatatgggc caggaggcgg gggcggcagc agtagcccaa gcgatgctgg gcctgtagcc 1380 ccctatggct acactcggcc ccctcagggg ctggcaagcc aggagggtga cttctctgcc 1440 tctgaagtgt ggtatcctgg cggagttgtg aacagagtcc cctatcccag tcccagttgt 1500 gttaaaagtg aaatgggacc ttggatggag aactactccg gaccttatgg ggacatgcgt 1560 ttggacagta ccagggacca cgttttaccc atcgactatt acttcccacc ccagaagacc 1620 tgcctgatct gtggagatga agcttctggt tgtcactacg gagctctcac ttgtggcagc 1680 tgcaaggtct tcttcaaaag agctgcggaa gggaaacaga agtatctatg tgccagcaga 1740 aatgattgca ccattgataa atttcggagg aaaaattgtc catcgtgtcg tctccggaaa 1800 tgttatgaag cagggatgac tctgggagct cgtaagctga agaaacttgg aaatctcaaa 1860 ctacaggaag aaggagaaaa ctccagtgct ggtagcccca ctgaggaccc atcccagaag 1920 atgactgtat cacacattga aggctatgaa tgtcaaccta tctttcttaa tgtcctggaa 1980 gccattgagc caggagtggt gtgtgccgga catgacaaca accagcctga ttcctttgct 2040 gccttgttat ctagtctcaa cgagcttggc gagagacagc ttgtacatgt ggtcaagtgg 2100 gccaaggcct tgcctggctt ccgcaacttg catgtggatg accagatggc agtcattcag 2160 tattcctgga tgggactgat ggtatttgcc atgggttggc ggtccttcac taatgtcaac 2220 tctaggatgc tctactttgc acctgacctg gttttcaatg agtatcgcat gcacaagtct 2280 cgaatgtaca gccagtgcgt gaggatgagg cacctttctc aagagtttgg atggctccag 2340 ataacccccc aggaattcct gtgcatgaaa gcactgctac tcttcagcat tattccagtg 2400 gatgggctga aaaatcaaaa attctttgat gaacttcgaa tgaactacat caaggaactt 2460 gatcgcatca ttgcatgcaa aagaaaaaat cccacatcct gctcaaggcg cttctaccag 2520 ctcaccaagc tcctggattc tgtgcagcct attgcaagag agctgcatca attcactttt 2580 gacctgctaa tcaagtccca tatggtgagc gtggactttc ctgaaatgat ggcagagatc 2640 atctctgtgc aagtgcccaa gatcctttct gggaaagtca agcccatcta tttccacaca 2700 cagtga 2706 5 589 DNA Artificial CMV promoter 5 tagttattaa tagtaatcaa ttacggggtc attagttcat agcccatata tggagttccg 60 cgttacataa cttacggtaa atggcccgcc tggctgaccg cccaacgacc cccgcccatt 120 gacgtcaata atgacgtatg ttcccatagt aacgccaata gggactttcc attgacgtca 180 atgggtggag tatttacggt aaactgccca cttggcagta catcaagtgt atcatatgcc 240 aagtacgccc cctattgacg tcaatgacgg taaatggccc gcctggcatt atgcccagta 300 catgacctta tgggactttc ctacttggca gtacatctac gtattagtca tcgctattac 360 catggtgatg cggttttggc agtacatcaa tgggcgtgga tagcggtttg actcacgggg 420 atttccaagt ctccacccca ttgacgtcaa tgggagtttg ttttggcacc aaaatcaacg 480 ggactttcca aaatgtcgta acaactccgc cccattgacg caaatgggcg gtaggcgtgt 540 acggtgggag gtctatataa gcagagctgg tttagtgaac cgtcagatc 589 6 11 DNA Artificial DR-1 6 ggaacggaac a 11 7 29 DNA Artificial DR-1(F) 7 tcgagtcctg aaggaacgga acagactga 29 8 29 DNA Artificial DR-1(R) 8 tcgatcagtc tgttccgttc cttcaggac 29 9 26 DNA Artificial 1XDR-1(F) 9 cgtcctgaag gaacggaaca gactga 26 10 37 DNA Artificial 1XDR-1(R) 10 tcgatcagtc tgttccgttt ttccttcagg acgagct 37 11 21 DNA Artificial upstream primer 11 cttggcttgc tttgctattt a 21 12 21 DNA Artificial downstream primer 12 atgtggtatg gctgattatg a 21 13 21 DNA Artificial LUC (F) 13 ggtaacccag tagatccaga g 21 14 22 DNA Artificial LUC (R) 14 ggaagacgcc aaaaacataa ag 22 

1. A transgenic non-human mammal whose genome comprises a nucleic acid construct, wherein said construct comprises a reporter nucleic acid encoding a reporter operably linked to a promoter comprising an androgen response element (ARE), and said construct further comprises an androgen receptor nucleic acid encoding an androgen receptor, and wherein expression of said reporter nucleic acid is regulated by expression of said androgen receptor nucleic acid.
 2. The transgenic non-human mammal of claim 1 wherein said reporter is luciferase.
 3. The transgenic non-human mammal of claim 1 wherein said androgen response element is 2×DR-1.
 4. A cell isolated from the transgenic mouse of claim 1, wherein the genome of said cell comprises said nucleic acid construct.
 5. The cell of claim 4 wherein said reporter is luciferase.
 6. The cell of claim 4 wherein said androgen response element is 2×DR-1.
 7. A mouse cell line comprising the cell of claim
 4. 8. An isolated nucleic acid construct that comprises a reporter nucleic acid encoding a reporter operably linked to a promoter comprising an androgen response element (ARE), and said construct further comprises an androgen receptor nucleic acid encoding an androgen receptor, and wherein expression of said reporter nucleic acid is regulated by expression of said androgen receptor nucleic acid.
 9. The construct of claim 8 wherein said reporter is luciferase.
 10. The construct of claim 8 wherein said androgen response element is 2×DR-1.
 11. A method for obtaining a target mouse whose genome comprises a nucleic acid construct, wherein said construct comprises a reporter nucleic acid encoding a reporter operably linked to a promoter comprising an androgen response element (ARE), and said construct further comprises an androgen receptor nucleic acid encoding an androgen receptor, and wherein expression of said reporter nucleic acid is regulated by expression of said androgen receptor nucleic acid, wherein said mouse can be bred to produce progeny mice whose genomes comprise said nucleic acid construct, said method comprising the steps of: (a) solating a fertilized egg from a first female mouse; (b) transferring a transgene comprising said nucleic acid construct into the fertilized egg; (c) transferring the fertilized egg of step (b) to the uterus of a pseudopregnant second female mouse; and (d) maintaining said second female mouse such that: (i) said second female mouse becomes pregnant with an embryo derived from said fertilized egg of step (c); (ii) said embryo develops into said target mouse; and (iii) said target mouse is viably born from said second female mouse; wherein the genome of said target mouse comprises said nucleic acid construct and wherein said mouse can be bred to produce progeny mice whose genomes comprise said nucleic acid construct.
 12. A method for producing a transgenic mouse cell line that expresses a reporter nucleic acid, said method comprising: (a) isolating cells from the transgenic mouse of claim 1; and (b) placing the isolated cells under conditions to maintain growth and viability of the isolated cells such that said transgenic mouse cell line expresses said reporter nucleic acid.
 13. A method of screening for a modulator of the androgen receptor, comprising administering a test substance to the transgenic non-human mammal of claim 1 and assaying the effect of said test substance on the activity of the androgen receptor.
 14. A transgenic non-human mammal whose genome comprises a nucleic acid construct, wherein said construct comprises a reporter nucleic acid encoding a reporter operably linked to a promoter comprising an androgen response element (ARE), and said construct further comprises an androgen receptor nucleic acid encoding an androgen receptor, and wherein said non-human mammal expresses said reporter nucleic acid in organs when said androgen receptor nucleic acid is expressed. 